The authorities in Dhaka, Bangladesh’s capital, however, also dismissed some elements of the Singaporean warning, saying there was no evidence that the workers had links to Al Qaeda or the Islamic State group or that they were planning an attack in Bangladesh.

Of the 27 workers deported by Singapore in December, 13 have been released and allowed to return to their families, because, though they subscribe to radical views, they had not violated any law, said Monirul Islam, the joint commissioner of the detective branch of the Dhaka metropolitan police.

“We will keep our watch on them,” he said. “They will be under our surveillance.”

Mr. Islam said that the 14 men who had been charged “were mentally ready to get involved with terror activities at any time,” but that the police had not found “any specific plan of carrying out an attack on any particular target.”

Singapore announced last week that its law enforcement agencies had identified 27 Bangladeshis, members of a “closed religious study group,” who “had become radicalized and were planning attacks back home.”

A statement from Singapore’s Home Ministry said the deportees “supported the armed jihad ideology of terrorist groups like Al Qaeda and the Islamic State in Iraq and Syria.” Among their possessions, the Singaporean authorities found diagrams apparently used to instruct men in “silent killing” and videos that showed young children training with firearms.

“While they were planning attacks outside Singapore, they could have easily changed their minds and attacked Singapore,” said Kasiviswanathan Shanmugam, Singapore’s minister for home affairs, in a Facebook post.

The deportation is a new and unwelcome development for Bangladesh, which is heavily dependent on remittances from hundreds of thousands of contract workers in Malaysia, Singapore and other countries.

Bangladesh, a vast democracy that has traditionally embraced a moderate form of Islam, has been struggling to combat a rise in extremist violence at home, including unusual attacks on Bangladesh’s tiny minority of Shiite Muslims.

The police in Singapore said the deported construction workers met weekly to discuss “armed jihad,” and “carefully targeted the recruitment of other Bangladeshi nationals to grow their membership.”

In interviews, several of the workers told Singaporean officials that they supported attacks on Shiite Muslims, whom they considered “deviant,” and that they were encouraged to return to Bangladesh and “wage armed jihad” against the government, the statement said.

After interviewing the deportees, the Bangladeshi authorities concluded that they had embraced radical Islam in Singapore, not in Bangladesh.

The 14 men now facing charges were followers of the Ansarullah Bangla Team, a hard-line Islamist group that has claimed responsibility for a series of gory targeted assassinations of secular writers, Mr. Islam said.

He added that several of the men were “close aides” of Jasimuddin Rahmani, the leader of the Ansarullah Bangla Team, who is now serving a prison sentence in Bangladesh.

He said investigators “did not find their link with any foreign militant organization.”

In recent months, social media accounts linked to both Al Qaeda and the Islamic State group have claimed responsibility for attacks carried out in Bangladesh, but the Bangladeshi government has dismissed the claims, attributing the violence to domestic militant networks, some associated with the political opposition.

Rohan Gunaratna, a terrorism expert at the S. Rajaratnam School of International Studies in Singapore, said the Bangladeshi government was wary that any indication that transnational jihadi groups were active in Bangladesh would discourage tourists and foreign investors.

“This fits with the government’s adamant stance that there is no I.S. connection in Bangladesh,” he said, referring to the Islamic State. “In the past, they always said attacks were not by Al Qaeda, and now they are saying the attacks were not by I.S.”

Mr. Gunaratna said that the Singaporean government was in a state of high alert after the discovery of the Bangladeshi group, and that he expected officials to continue investigations into the group’s activities in the coming months and years.

A spokeswoman for Singapore’s Home Ministry said Saturday that the 27 Bangladeshis “supported the armed jihad ideology of terrorist groups and several contemplated traveling to and participating in armed jihad in the Middle East and Bangladesh.”

Correction:

An article last Sunday about the filing of terrorism charges in Bangladesh against 14 Bangladeshi construction workers deported from Singapore misstated the timing of their deportation. It was in December, not the middle of January.